The injured were immediately rushed to the district hospital here. Three critically injured people were later referred to the trauma centre in Lucknow for further treatment, the police said.
"A major accident has taken place due to a collision between a tanker and a tractor-trolley. Unfortunately, six have died so far. Seven people are injured. Teams of medical and police have been pressed into action," Sitapur SP L R Kumar said.
Witnesses said there were as many as 40 people travelling in the trolley when the accident took place.